Journal of Water and Wastewater Science and Engineering

Journal of Water and Wastewater Science and Engineering

Investigating the Amount of Microplastics in Wastewater Treatment Plant Effluent and Sludge and the Efficiency of Units in Removing Microplastics

Document Type : Review Paper

Authors
Masoume Taherian 1
Afshin Takdastan 2
Reza Dehbandi 3
Neemat Jaafarzadeh 2
Mohammad javad Mohammadi 4
1 M.Sc. Student, Student Research Committee, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2 Professor, Environmental Technologies Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
3 Assistant Professor, Department of Chemical Engineering, University of Science and Technology of Mazandaran, Behshahr, Iran. School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.
4 Assistant Professor, Environmental Technologies Research Center, Medical Basic Sciences Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
10.22112/jwwse.2025.436312.1396
Abstract
The aim of this paper is to investigate the quantitative and qualitative characteristics of microplastics in the effluent and sludge of municipal wastewater treatment plants (WWTPs), as well as the removal efficiency of individual treatment units in eliminating microplastics from wastewater. In this review study, based on global experience and an assessment of recent and reliable international and Iranian studies, relevant articles published between 2011 and 2023 were searched in the SID, ScienceDirect, Google Scholar, and Scopus databases using the keywords wastewater, microplastics, wastewater treatment plant, sewage sludge, and treatment units. According to the reviewed studies, the lowest reported removal efficiency was 73% (188 MPs/L in influent wastewater and 50 MPs/L in effluent), while the highest removal efficiency reached 97.8% (69 MPs/L in influent wastewater and 1.73 MPs/L in effluent). In addition, the average microplastic removal efficiencies achieved by grit chambers, primary sedimentation, and secondary sedimentation were 44.95%, 52.9%, and 73.73%, respectively. The lowest and highest concentrations of microplastics in treated sludge were 510 and 4.95 × 10⁵ particles per kilogram of dry sludge weight, respectively. Based on the findings, the main mechanisms responsible for microplastic removal from wastewater include screening, surface adsorption, sedimentation, and attachment to biological aggregates, depending on the polymer type.
Keywords
Effluent
Microplastics
Wastewater Treatment Plant
Sewage Sludge and Treatment Plant Units
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Journal of Water and Wastewater Science and Engineering
Volume 10, Issue 3
Autumn 2025
Pages 3-10

  • Receive Date 17 January 2024
  • Revise Date 07 July 2025
  • Accept Date 19 July 2025